Among other things this brief essay argues against the notion of dualism, that is, the idea that mental and physical processes are entirely different.
It’s easy to understand how this notion arose. Dualism is intuitive. Consciousness does seem to be something unto itself. Awareness seems wispy and insubstantial, while the physical world seems heavy and solid. It’s only a small step to conclude the two things are fundamentally different.
Although virtually all neuroscientists reject this idea, it has a long history in other disciplines. The notion of some kind of soul separate from the body is central to several religions of course, and indeed religion is the primary source of dualistic thinking in contemporary life. But this is far from a religious matter only.
Since Descartes unveiled his version of dualism nearly four centuries ago, philosophers have continued to debate the issue. More recently, and most famously, the philosopher David Chalmers introduced his notion of “the hard problem of consciousness”. By this he referred to our profound inability to explain, or even imagine, how subjective experience--a seemingly nonphysical essence--could ever possibly emerge from a purely physical system. How could such a system ever yield, to invoke a common example, the subjective experience of redness?
Since we have so far failed to solve this conundrum, some philosophers suggest we must retreat to dualism. Others recommend embracing a different variation of materialism. And probably the best known example of the latter is known as panpsychism.
This perspective has a long intellectual history and is, among some, now back in vogue. It asserts that consciousness is ubiquitous. That awareness pervades all matter, right down to the subatomic level, at least in some rudimenatary sense. Consciousness does not need to emerge from the physical because it is already within it, intrinsically.
Dualism, materialism, panpsychism. There are several different paradigms here, and all have limitations. Some more than others.
First, dualism. What do we find when we look inside the skull? We find the same basic things we find everywhere else in the universe: matter and its alter ego, energy. Do what you will, surgery, EEGs, fMRIs, MEGs, it’s still just matter and energy. If consciousness is some other kind of basic reality, separate from the other building blocks of the universe, we haven’t been able to find it.
Furthermore, if the mind and the physical world are indeed basically different, they certainly seem to have an extremely close relationship. A tiny electrical current applied to one site on the brain might bring forth, say, a particular sensation. But the ingestion of a psychedelic substance, affecting many areas of the brain, will bring forth considerably more than that: a radical change in the entire spectrum of experience. Conversely, the biological changes of sleep only reduce awareness, while the end of biological processes--that is, death--eliminates awareness entirely.
Dualism would have us believe that even though consciousness seems to occur only in nervous systems, and furthermore that it reliably changes when those systems change, still it is not a function of those systems. It is instead a completely different, mysterious kind of reality that just happens to accompany those systems.
Panpsychism introduces its own considerable difficulties. Of course no one has been able to demonstrate that consciousness is somehow intrinsic to all matter. No one has been able to discern how that might be attempted. Like dualism, it has not been a particularly useful paradigm for research.
Furthermore, the theory does not seem to offer any increase in explanatory power. It leaves entirely unexplained, for example, how the supposed rudimentary consciousness of tiny particles could somehow combine to generate a more complex awareness. In other words, it has its own version of an unexplained emergence. Not to mention why that emergence seems to occur in elephants, for example, but not in boulders.
Admittedly, in meditative states I occasionally resonate with something akin to a panpsychic sensibility. (See "Make Me One With Everything", another of my essays on this site.) But as a day to day working paradigm my own perspective is like that of neuroscientists: a garden variety materialism. That is, I view all known varieties of consciousness as emerging in nervous systems out of the interactive processes of matter and energy.
Now as noted previously, at present there is no detailed explanation for how this might happen. So clearly materialism has not yet solved the problem. But the paradigm is at least consistent with all available evidence, and parsimoniously so, without introducing new realms of reality. And of course it has proven valuable as a framework for research. It is likely to be the reigning paradigm for some time, and with good reason.
Some critics, undoubtedly feeling rather clever, compare materialist models of consciousness to the old joke about the drunk. He loses his keys one night and searches for them under a streetlamp. But he knows he did not lose them there. He's only looking there because the light is better.
As a metaphor for materialism this has an element of truth, but it is also a distortion. When it comes to subjective experience we are in fact not sure where we lost the keys. We're looking under the streetlamp not only because we can, but because they might be there, and if so we might eventually find them. The dualist alternative is to declare them as definitely in the dark, and abandon the search. As Daniel Dennett has rightly observed, "dualism is giving up."
Although I have reasonable confidence in the materialist paradigm, it's wise to be epistemologically modest. After all it might well be true, as the position called "mysterianism" suggests, that as a species we are not capable of ever truly understanding consciousness. But I doubt it.
What I do not doubt is that even when we come to understand it abstractly, that will not be enough. Even when the biology of consciousness is comprehensively detailed, we will still feel disappointed. Abstract explanations will never seem to capture our experience, and always the narrative will be unsatisfying. Intuitively at least, the hand will never be able to grasp itself.
And coming upon good abstract explanations will be difficult enough, given the staggering complexity of the subject matter. A human brain has about 86 billion neurons; it may also have 100 trillion synapses, and perhaps several times that many. We clearly have our work cut out for us.
However, perhaps that extreme level of complexity is not the key. Countless connections might shape the range of what we can do with our brain, but maybe something "simpler" in a biological sense lay behind subjective experience itself. Some neuroscientists believe the sense of subjectivity might be explained by a self-reflective process, that is, awareness of awareness. There is some evidence suggesting sites in the brain from which this might originate. This line seems promising to me, but of course it is still only a start.
At this point all we can really say with confidence is that research will continue. And that with any luck, perhaps consciousness may yet reveal some of its mysteries.